I am making my girls run laps. They get a warning now and then off they go.
They see one sent to run the rest seem to straighten up pretty quickly.
I have just started seeing this issue my last three practices.
I used to work for a cheer gym that believed in "disciplining with natural consequences." If a child was not listening or not following instructions or showing little interest and being disruptive, the natural consequence would be not being allowed to participate.
Without getting angry, we would gently say something like "Since this doesn't seem to interest you, go sit over there and you may join us when you're ready to participate."
In my experience, 3 minutes is about all it takes. Generally, they're a bit embarrassed not being part of the group, and watching everyone else have fun makes them wish they were there too.
It works best on young children, but I tried it on a varsity girl, and despite being very clearly annoyed, she didn't give me any attitude the rest of practice.